List of knotty synonyms and knotty related words.
Byzantine, Herculean, abstruse, arduous, beyond one, brutal, burled, complex, complicated, crabbed, cramp, critical, daedal, delicate, demanding, difficile, difficult, effortful, elaborate, exacting, formidable, garbled, gnarled, gnarly, gordian, hairy, hard, hard to understand, hard-earned, hard-fought, intricate, involved, jawbreaking, jumbled, knobbed, knobbly, knobby, knoblike, knotted, knurled, knurly, laborious, labyrinthine, lumpy, mean, no picnic, nodal, noded, nodiform, nodose, nodular, nodulated, noduled, not easy, nubbled, nubbly, nubby, obfuscated, obscure, obscured, operose, overtechnical, perplexed, rigorous, rough, rugged, scrambled, set with thorns, severe, sophisticated, spiny, steep, sticky, strenuous, studded, terrible, thorny, ticklish, toilsome, torose, tough, tricky, tubercular, tuberculous, tuberose, tuberous, uphill, wicked